Bottom Line:
Two dinuclear cobalt complexes based on bis-diketonate ligands (ligand 1: 3,3'-(1,3-phenylene)bis(1-phenylpropane-1,3-dione); ligand 2: 3,3'-(1,4-phenylene)bis(1-phenylpropane-1,3-dione)) were successfully synthesized.The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities.All these improvements facilitate the implementation of the acrylate CMRP and open the door to the scale-up of the syntheses and applications of the multicomponent low polydispersity polymers.

ABSTRACTTwo dinuclear cobalt complexes based on bis-diketonate ligands (ligand 1: 3,3'-(1,3-phenylene)bis(1-phenylpropane-1,3-dione); ligand 2: 3,3'-(1,4-phenylene)bis(1-phenylpropane-1,3-dione)) were successfully synthesized. The two neutral catalysts all showed satisfactory activities in the cobalt-mediated radical polymerization (CMRP) of methyl methacrylate (MMA) with the common initiator of azodiisobutyronitrile (AIBN). The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities. Mono- or dicomponent low polydispersity polymers could be obtained by using the two dinuclear catalysts under proper reaction conditions. All these improvements facilitate the implementation of the acrylate CMRP and open the door to the scale-up of the syntheses and applications of the multicomponent low polydispersity polymers.

Mentions:
The structure of ligand 2 has already been reported by Soldatov et al [19]. Two different crystalline forms of the H2L2 were isolated in that paper. As the forms were distinct (as attested by solid state experimental characterization), they were thus confirmed as polymorphs. The crystal structure of H2L2 (Figure 1) shows a planar structure with the two diketonate units in trans- arrangement to maximized conjugation. The two crystal cell parameters of the ligand 2 obtained by Soldatov group are distinct to the ligand 2 reported by our group. Similarly, the ligand 2 of this paper could be seen as the third polymorphs.

Mentions:
The structure of ligand 2 has already been reported by Soldatov et al [19]. Two different crystalline forms of the H2L2 were isolated in that paper. As the forms were distinct (as attested by solid state experimental characterization), they were thus confirmed as polymorphs. The crystal structure of H2L2 (Figure 1) shows a planar structure with the two diketonate units in trans- arrangement to maximized conjugation. The two crystal cell parameters of the ligand 2 obtained by Soldatov group are distinct to the ligand 2 reported by our group. Similarly, the ligand 2 of this paper could be seen as the third polymorphs.

Bottom Line:
Two dinuclear cobalt complexes based on bis-diketonate ligands (ligand 1: 3,3'-(1,3-phenylene)bis(1-phenylpropane-1,3-dione); ligand 2: 3,3'-(1,4-phenylene)bis(1-phenylpropane-1,3-dione)) were successfully synthesized.The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities.All these improvements facilitate the implementation of the acrylate CMRP and open the door to the scale-up of the syntheses and applications of the multicomponent low polydispersity polymers.

ABSTRACTTwo dinuclear cobalt complexes based on bis-diketonate ligands (ligand 1: 3,3'-(1,3-phenylene)bis(1-phenylpropane-1,3-dione); ligand 2: 3,3'-(1,4-phenylene)bis(1-phenylpropane-1,3-dione)) were successfully synthesized. The two neutral catalysts all showed satisfactory activities in the cobalt-mediated radical polymerization (CMRP) of methyl methacrylate (MMA) with the common initiator of azodiisobutyronitrile (AIBN). The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities. Mono- or dicomponent low polydispersity polymers could be obtained by using the two dinuclear catalysts under proper reaction conditions. All these improvements facilitate the implementation of the acrylate CMRP and open the door to the scale-up of the syntheses and applications of the multicomponent low polydispersity polymers.